Celiac disease, evidenced by sensitivity to the gluten fraction of wheat flour often first appears in early childhood. The proposed work is designed as a comparison of the amylase inhibitor from wheat flour with alpha-gliadin (which has been shown to induce the symptoms in celiac patients) in an attempt to determine if they are identical substances. Preliminary experiments have revealed similarities with respect to solubility properties in aqueous alcohol, amino acid composition and electrophoretic mobility. The proteins will be further characterized to compare their physical and chemical properties. Terminal residues will be determined, and fingerprint patterns obtained following tryptic digestion will be compared. Sequence analysis of peptides from the amylase inhibitor will be initiated. Peptides released by digestion of gliadin with pepsin, trypsin and pancreatin will be fractionated and tested for their effects on lysosomes from rat liver. The fraction causing lysosomal disruption will be studied further since it has been also implicated in celiac toxicity. The peptide fractions will be compared to peptides obtained from a similar digestion of the amylase inhibitor and alpha-gliadin to see if these proteins are the source of lysosomal disrupting peptides. Evidence obtained from these studies definitively establish whether the amylase inhibitor is related to the protein and peptides able to induce the celiac symptoms. In addition, the inhibitor will be modified chemically as part of a study of its site of action and mode of interaction with alpha-amylase. The modified protein may yield insight into potential methods for controlling the disease by modifying wheat products so that patients may be able to consume a more normal type diet.